Episode 52. AJ Climate Champions with Hattie Hartman and Joe Jack Williams. 

To achieve replication at scale, Nicolas Coeckelberghs of Brussels-based BC Materials favours compressed earth blocks over rammed earth.

‘Our goal is to bring earthen construction from a niche to a growing market,’ says  Coeckelberghs. He likens this challenge to playing chess on multiple fronts, creating demand while simultaneously supplying the market. While acknowledging the aesthetic appeal of rammed earth,  Coeckelberghs cautions that it is technically complex and unaffordable at scale.

In this episode, Coeckelberghs describes BC Architects’ 15-year trajectory from its first earth building in Burundi, to the proliferation of collaborative workshops which led to a strand of consultancy work, to the creation of cooperative BC Materials in 2018. This led in turn to the recent launch of Léém, a manufacturing company that produces circular materials: unfired bricks, and clay plasters and paints.

While  Coeckelberghs is an innovator, he is also pragmatic and advocates focusing on easy wins. ‘Don’t use earth to make facades, just use it to make structures inside,’ he says. He sees enormous scope for application of earth blocks internally where they are protected from the weather and hence more durable.

In search of a way to scale the earth blocks production, BC Materials visited concrete and brick manufacturers across Belgium to understand their manufacturing techniques and explore possibilities for collaboration. Partnerships with large manufacturers are now underway, and BC Materials produces its blocks through  ‘industrial co-working’,  using the larger plants’ production line during their ‘off’ hours.

For show notes and to catch up on all AJ Climate Champions episodes, click here.

Episode 51. AJ Climate Champions with Hattie Hartman and Joe Jack Williams. 

Daniel views mud and waste as opportunities, not obstacles. He advocates an approach of ‘maximum optimism’, explaining that mud and waste enhance his designs. ‘I follow the materials; they do not follow me,’ he says.

Sourcing materials primarily from within five miles of a site, Daniel describes how mud and waste can be transformed into beautiful buildings. But this was not the case from the outset.  Daniel first incorporated waste bottles into an early project because the budget ran out before the windows had been purchased. He then realised that a new aesthetic had emerged from this approach.

Daniel argues that architects need to be on site, not in the office, in order to observe their surroundings. ‘Open your eyes. Be out there!’ he advises. Architecture is not a white collar job; it’s about going to site, according to Daniel. ‘Today architects are not able to see because we are simply oblivious to what is happening around us. This way of practice has to change,’ he insists.

Daniel’s ambition is to bring earth construction to the mainstream and he is not opposed to adding small amounts of cement to his earth mixes to increase structural strength. ‘We need to enter commercial construction. If that means using a bit more steel or cement than the purest form of mud architecture, I’m open to it,’ he says.

For show notes and to catch up on all AJ Climate Champions episodes, click here.

Episode 42. AJ Climate Champions with Hattie Hartman and George Morgan. Montreal-based architect and systems thinker Scott Francisco explains why architects must educate themselves to understand the nuances of timber sourcing.

Francisco believes that greater use of timber in construction in coming decades will be essential to meet our climate targets. This in turn means an increase in plantation forestry, but this can be achieved without compromising biodiversity. 

He also explains why it’s crucial for designers to have a holistic understanding of the timber supply chain. While timber certification is important, relying on certification alone is not enough. He outlines the range of factors that impact the carbon footprint of timber and how to understand different sourcing strategies.

Architects can play an important role in specifying ecological timber by asking the right questions and educating themselves to understand that specifying a species and a grade is not enough. In some instances, particularly on smaller projects, architects can construct a timber value chain for a particular building.

For show notes and to catch up on all AJ Climate Champions episodes, click here.

Episode 41. AJ Climate Champions with Hattie Hartman and George Morgan. In this episode, AJ100 Sustainability Champion and Architype associate director Ann-Marie Fallon discusses her belief that delivering net zero is not just technical – understanding how people use buildings and their role in the community is crucial.

We also hear about Architype’s success in influencing policy changes in Scotland, including a Passivhaus equivalence standard for all new housing. Fallon describes the growing community of architectural practices in Scotland pushing for more sustainable outcomes.

Fallon has been instrumental in developing a ‘blended’ approach to retrofit through a nuanced study of the city of Edinburgh’s estate of 300 buildings with a wide variety of building typologies from different eras. This holistic approach involves everything from exploring whether the activities in a particular building can be consolidated and intensified to the nitty gritty of updating mechanical plant. 

For full show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Bonus episode. AJ Climate Champions with Hattie Hartman. During an Obel Award panel at the UIA conference in Copenhagen, Heringer seized the opportunity to ask the global audience for ‘forgiveness’ on behalf of architects of the global north.

‘I'm sorry for creating this … ideal of an architecture that was supposed to bring us a comfortable, safe and happy and healthy life, when in fact, it was just exploiting the planet and adding to social injustice,’ she said.

Winner of four important awards since our last interview in episode 6, Anna explains how earthen architecture is gaining traction and describes her ongoing work in Ghana and at the St Michael Campus for Sustainability in Traunstein, Germany.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 40. AJ Climate Champions with Hattie Hartman. In this episode, we explore the global phenomenon of shrinking villages in the countryside, hearing about a remarkable series of interventions in southeastern China by DnA_Design, a small Beijing practice. 

Xu advocates a role change for architects in both rural and urban contexts. Architects should no longer accept a commission as given, but take the initiative and evaluate a project’s regional context to make a proposal that is unique and rooted in its place.

In less than a decade, Xu and her team have built more than 20 projects that vary widely in programme and materiality: a tofu factory, a museum, performance spaces and a sugar factory. These projects have attracted new residents back to formerly dilapidated villages by creating jobs and a sense of purpose in these forgotten places.

CHRISTMAS GIVEAWAY Win a copy of Greta Thunberg’s The Climate Book (Penguin 2022). We have two copies to give away. To enter the prize draw,  email hattie.hartman@emap.com with your name, address, affiliation and a testimonial about the podcast before 15 January 2023. We will choose the winners in the new year.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 38. AJ Climate Champions with Hattie Hartman. Slade, head of historic building climate change adaptation at Historic England, explains why insulation is the area of highest risk.

As a conservation-accredited building surveyor with deep interests in both the natural and built environment, Slade explains the role of Historic England as a statutory consultee in planning, in provision of technical guidance and training, and in research to confront upcoming climate challenges. In this episode, she argues that sustainability and conservation are ‘well-matched’ to deliver change on the ground.

Slade also details the range of guidance and webinars available from Historic England, as well as the current research agenda which includes ‘hazard mapping’ of regional risks. This involves granular mapping of overheating, flooding, slope collapse, shrink-swell capacity and storm exposure under different emissions scenarios and their implications for the built environment.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 38. AJ Climate Champions with Hattie Hartman.In our second episode exploring how sustainability impacts heritage buildings, we speak to Procter-Rihl Architects’ Chris Procter, lead author of ACAN’s Climate Emergency Conservation Area Toolkit – England. Chris explains how conservation areas can streamline the consent process by developing a pattern book approach to building elements.

Chris’ detailed audit of Islington’s Cross Street Conservation Area found that two-thirds of existing single-glazed windows could be suitable for double or triple-glazing, 44% of solid external walls could be wrapped in external wall insulation and over 30% of roofs could be fitted with solar panels.

Chris also delves into the sensitive topic of window replacement, arguing that if existing windows do not conform to the original window pattern of a building, they should qualify for upgrading. He advocates development of a pattern book of details, complete with approved manufacturers, to simplify the consent process for building owners, relieve planners’ workloads, and speed up retrofit. Chris argues that this should be done locally based on specific building types.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 37. AJ Climate Champions with Hattie Hartman. 5th Studio co-founder Oliver Smith shares his radical approach to upgrading listed buildings. He talks about the practice’s radical retrofit of New Court at Trinity College, Cambridge. Completed in 2016, New Court remains a trailblazing project because it pioneered an ambitious sustainability agenda in a Grade I-listed building using a nuanced approach that balanced heritage concerns with upgrading thermal and energy performance and internal comfort. 

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 36. AJ Climate Champions with Hattie Hartman. In this episode, Pelsmakers argues that teaching values must be at the heart of architectural education. She believes students are bombarded with too much technical information on sustainability and that a strong grounding in architectural ethics is essential in order to apply technical knowledge for the best possible built environment and social equity outcomes. This approach requires not only new curriculum content, but a shift from master-apprentice to more democratic and inclusive peer-to-peer learning.

Sharing insights from having taught recently in seven different schools of architecture, structural engineer and educator Cíaran Malik notes that curriculum reform has not kept pace with students’ demands for change and that retrofit remains a minority topic. Malik argues that once students develop an intuitive understanding, grounded in evidence, they can begin to experiment with results that are both ‘beautiful and exciting.’

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 35. AJ Climate Champions with Hattie Hartman. Environmental engineer Patrick Bellew of Atelier Ten shares insight from having worked on high-profile architectural projects, including the new Google HQ at King's Cross designed by Heatherwick Studio. He explains that post-pandemic ventilation rates in commercial offices have tripled with radiant solutions replacing blown air systems, and how this can be done while still controlling energy use. 

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

In association with Velux

Episode 34. AJ Climate Champions with Hattie Hartman. Glasgow climate activist Scott McAulay and ACAN’s Rosie Murphy advocate for a curriculum which empowers students as changemakers.

McAulay, founder of the virtual Anthropocene Architecture School, argues that the answer to every brief should not be a new building. Architects must rethink their role as stewards of the built environment rather than designers, and students should be taught to scrutinise a brief in its larger context. Perhaps a vacant or underutilised building nearby can be transformed to meet a client’s needs.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

In association with Velux

Episode 50. AJ Climate Champions with Hattie Hartman and Joe Jack Williams. 

Carmody Groarke sustainability lead Sian Ricketts explains how architecture can adapt to the reality of finite resources and an abundance of waste.

Ricketts says that architects should develop their intuition and new rules of thumb to design for a changing climate. Architecture needs to adapt to incorporate materials from waste streams, and this requires a new approach to detailing and ongoing maintenance. ‘The industry is going through a huge learning process and we should not be scared of getting it wrong,’ she says. Marginal gains on every project are important.

In this episode, Ricketts describes the process of developing a bespoke brick for the Design Museum Gent in Belgium. She explains that the practice did not start with a bespoke brick in mind. Because conventional clay-fired bricks are high in embodied carbon, an exploration of less carbon intensive alternatives led to an in depth collaboration with Local Works Studio and Brussels-based bcmaterials that in turn led to incorporating local waste streams into the design of the new brick.

Ricketts observes that the process of developing the bespoke brick for Ghent has strengthened the practice’s confidence in seeking opportunities for both innovation and circularity in future projects. Carmody Groarke is currently working with Imperial College-based startup Seratech to explore the use of magnesium carbonate as a binder for bricks.

For show notes and to catch up on all AJ Climate Champions episodes, click here.

Episode 33. AJ Climate Champions with Hattie Hartman. Velux director of sustainable buildings Lone Feifer explains why ‘relative’ sustainability, improvement on previous standards, is no longer good enough. ‘One planet means one carbon budget with a fixed amount available for buildings,’ she says. It’s not about improving relative to previously accepted standards.

Lone also describes how Denmark’s new building regulations, effective in January 2023, will regulate whole life carbon by requiring life cycle assessment for projects and setting benchmarks for different building types. For homes, Feifer advocates the Active House Alliance’s adaptive comfort approach rather than the absolute comfort ranges prescribed by Passivhaus.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

In association with Velux

Episode 32. AJ Climate Champions with Hattie Hartman. In this episode, we speak to Louisa Bowles - winner of this year’s AJ100 Sustainability Champion award - about Hawkins\Brown’s two-pronged approach to sustainability: reducing carbon emissions and enhancing society. Louisa explains that in order to avoid the ‘smoke and mirrors’ of carbon offsets, calling a project 'net zero' should increasingly rely on annual operational energy reporting, public data disclosure and third-party verification.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episide 31. The Manchester-based Jo Sharples and Jack Richards of Editional Studio share top tips from Decarbonise Your House Now!, a timely domestic retrofit guide they have put together for clients and architects.

Each recommended retrofit measure is assessed in terms of ‘trigger points’ (if you’re doing X, consider Y) and ‘related opportunities’ (if you’re doing x, consider the optimal low carbon approach). Launched in late 2021, Decarbonise Your House Now! forms the basis of an ongoing exhibition in Editional Studio’s studio shopfront in Manchester’s Chorlton neighbourhood.

Episide 30. Retrofit expert Bob Prewett describes how a client’s brief for an ‘extreme retrofit’ in 2008 gave him ‘something bigger than architecture to think about’. Divided between London and Wells, the ten-strong Prewett Bizley Architects has a portfolio of completed retrofit projects that achieve upwards of 70% energy savings and regularly monitors its buildings to understand how they operate over time.

Although a founder member of the Passivhaus Trust, Bob observes that ‘we rarely push all the way to Passivhaus which is a bit strong for many heritage buildings’. Self-taught when retrofit resources, training and exemplar projects were scant, Bob explains the many ways architects can upskill today.

Episode 29. We speak to architect and ACAN (Architects Climate Action Network) steering group coordinator Sara Edmonds who is jumpstarting widespread conversations around domestic retrofit.

Reaching beyond the bounds of architecture, Studio seARCH co-founder and Passivhaus designer Sara Edmonds is engaged in inclusive conversations across the domestic retrofit space from the political to the practical, establishing ties with the New Economics Foundation and Insulate Britain.  

In this wide-ranging discussion, Sara describes what it will take to kickstart greater uptake of domestic retrofit in London and beyond: from DIY upskilling to empower householders to ensure that existing heating systems operate at maximum efficiency to lessons from Ireland’s national retrofitting scheme launched in February.

Episode 28. Architect John Christophers shares lessons from a decade of monitoring his own home which generates 40 per cent more energy than it uses. We continue our focus on building performance and explore what one can glean from monitoring a small project.

In 2013, John retrofitted and extended a two-up two-down Victorian terraced house in Birmingham’s Balsall Heath neighbourhood, adding Passivhaus levels of insulation and triple-glazing to the existing house. The extension features unfired load-bearing clay bricks and compacted earth floors, as well a monopitch roof that incorporates both PV and solar thermal.

Episode 27. We continue our focus on building performance; AHMM sustainability lead Craig Robertson shares important lessons from a building performance study of 2015 Stirling Prize-winning Burntwood School in southwest London. It is still much too rare for architects – and clients – to transparently share post-occupancy data, especially when it flags up a significant performance gap, so kudos to AHMM for sharing this study with us.

In the case of Burntwood School, heating loads were nine times the design prediction, while electricity loads were four times as much. Shocking as this may sound, it is not unusual. Craig explains why and what we need to do about it. A key premise of the study was to investigate the relationship between energy performance and indoor environmental quality. These must be looked at in tandem. Our conversation with Craig reveals, in practice, the many building performance issues we discussed in our last episode with Judit Kimpian.

Episode 26. A year after publication, Judit Kimpian and Hattie Hartman revisit key messages from the book they co-authored with Sofie Pelsmakers. Judit explains why building performance studies de-risk the construction process and help ensure that what was designed actually gets built and operates as intended. She explains why it is so important to stay with a project during a one-to-three-year ‘landing’ period after completion, to ensure proper commissioning, monitor both energy and indoor environmental quality, and talk to occupants.

Plus, you can WIN a copy of Energy|People|Buildings by J. Kimpian, H. Hartman and S. Pelsmakers (RIBA Publishing 2021). We have three copies to give away – details here.

Episode 25. AJ Climate Champions with Hattie Hartman. In this episode, we hear from structural engineer Hanif Kara who is working with leading architects on projects across the globe for ambitious clients with resources to deliver sustainable outcomes, including Google, Apple and British Land. Recent projects include Grafton’s Stirling-Prize winning Town House in Kingston, Grafton’s Marshall Building at the LSE, Foster + Partners' Bloomberg building and the new Google headquarters currently on site at King’s Cross with Bjarke Ingels and Thomas Heatherwick.

In contrast with most of our guests so far, Hanif is not a Climate Champion from way back, but we’re delighted to have him on the pod because he is at the forefront of what is being delivered on the ground now and his design-led approach is pushing best practice. In this episode, he advocates reverse-engineering as a forensic method that utilises complex computational methods to retrofit and extending existing buildings.

Episode 24. AJ Climate Champions with Hattie Hartman. In this episode, Soane Medal (2021) winner Tabassum describes her approach as distilling the essence of vernacular buildings into contemporary architecture

Working on the front line of climate change in the Ganges delta, Tabassum is developing flat pack bamboo homes to bolster marginal communities devastated by seasonal flooding.  ‘How relevant are we as a profession if we just cater our services to one per cent of the people?’, she asks.

Tabassum was recently short-listed in the London School of Economics’ competition for an academic building at 35 Lincoln’s Inn Fields as part of a team led John McAslan + Partners with Tod Williams/Billie Tsien Architects.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Ep 49. Structural engineer David Watson describes the enduring appeal of brick and its underexploited superpower: reuse

Brick has many advantages: durability, aesthetics, use as both envelope and structure, and the possibility of local (even artisanal) production. This last point differentiates it from steel and concrete, due to the Ordinary Portland Cement needed for concrete production. ‘We need to ‘build our intuition about what impacts embodied carbon and emissions from different materials,’ says Watson.

Watson highlights the importance of querying the firing required to achieve different finishes, because it varies between brick types and can significantly impact overall embodied carbon. It’s also important to understand the fuel used in the kilns where bricks are fired.  While in the UK this is predominantly natural gas, abroad it might be charcoal or coal, both of which generate significant amounts of particulates.

In non-loadbearing cladding applications, the embodied carbon of the support systems must be taken into account because they can comprise as much embodied carbon as the brick and mortar combined. These hidden impacts are often difficult to calculate due to lack of EPD data, explains Watson.

Brick reuse is on the increase but currently comprises less than five per cent of the market because of the challenge of removing the mortar, particularly those bound with Ordinary Portland Cement. Traditional lime-bound mortars are easier to remove. Current research is exploring mechanised removal of cement-bound mortars, and increased demand should prompt the market to respond, says Watson.

In this episode, we also discuss ConcreteZero targets (AKTII is a signatory) and the extent to which they rely on GGBS. Watson stresses the necessity of ‘using less’, for example, exploring ribbed, coffered or troughed slabs as an alternative to flat slabs. He advocates form-effective design, marrying structure with architectural expression in a lean use of materials.

David Watson can be contacted at david.watson@akt-uk.com.

To catch up on all episodes of AJ Climate Champions, click here.

Episode 23. AJ Climate Champions with Hattie Hartman. In this episode, we continue our focus on France, speaking to one of the country’s leading practitioners of ecological architecture. Over four decades, Philippe Madec has combined practice, teaching and writing. He has built extensively across France: housing, public buildings, and many urban design and masterplanning projects which feature abundant green spaces. He also explains why he is no longer interested in Passivhaus.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 22. AJ Climate Champions with Hattie Hartman. New year, new horizons: Climate Champions is going abroad in search of fresh approaches to ecological architecture. This week we continue talking to French architect and natural materials expert Dominique Gauzin-Müller, who explains why hybrid use of materials is the way forward. We also speak to French structural engineer and ACAN member Frédéric Bourgeon about France’s new embodied carbon regulations.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 21. AJ Climate Champions with Hattie Hartman. New year, new horizons: Climate Champions is going abroad in search of fresh approaches to ecological architecture. This week we talk to French architect and natural materials expert Dominique Gauzin-Müller about France’s growing ‘frugal’ architecture movement. She also shares with us research in ‘poured earth’ which she sees as an alternative to concrete.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 20. AJ Climate Champions with Hattie Hartman. As 2021 crawls to a close, Hattie Hartman converses with Design Museum chief curator Justin McGuirk about the exhibition Waste Age: What Can Design Do, on show until 22 February. And if you’re still wondering how your practice can tackle the climate emergency, Architects Declare steering group member Kat Scott reveals AD’s long-awaited Practice Guide, packed with tips for every practice – large or small – no matter where you are on your sustainability journey.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 19. AJ Climate Champions with Hattie Hartman. This week we continue our focus on reuse with a step-by-step approach to tagging the components of an existing building so that they can be dismantled and reused, just like Lego blocks. Hoolahan explains how she collaborated with a multidisciplinary team to develop an open source, design-led approach to material passports for retrofit, an initiative that won her this year’s AJ100 Sustainability Champion award.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 18. AJ Climate Champions with Hattie Hartman. Architect and academic Duncan Baker-Brown shares the latest developments in material reuse, including his proposal for a pavilion at Glyndebourne Opera, sourced from materials on the Glyndebourne estate and the surrounding Sussex weald.

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Episode 17. AJ Climate Champions with Hattie Hartman. In this episode, we speak to Glasgow City Council architect Paola Pasino about her work with Danish architect Jan Gehl to create the framework for much that is happening in Glasgow today. Our second guest is ACAN’s Evelyn Choy, who talks to us about the exhibitions, events and social media storm the Architects Climate Action Network (ACAN) is hosting during COP26. Hattie Hartman highlights the key built environment reports launched for the international climate conference. 

For show notes to this episode, go to www.architectsjournal.co.uk/podcasts

Ep 16. Continuing its focus on the international climate conference, AJ Climate Champions speaks to Becca Thomas of New Practice about activating a site just outside the COP26 secure zone as a destination for protesters, and Stephen O’Malley of Civic Engineers about redesigning the public realm of Glasgow city centre for active travel and resiliency.

For show notes to this episode and to catch up on all AJ Climate Champions episodes, click here.

The new RIBA president discusses his advocacy role at COP26, and the chair of the institute’s Sustainable Futures Group explains revisions to the 2030 Climate Challenge targets.

As COP26 in Glasgow approaches in early November, AJ Climate Champions puts the spotlight on the RIBA’s recently released Built for the Environment report, a global call for governments to harness the built environment’s role in tackling climate change. Allford shares his ambitions for a House of Architecture at 66 Portland Place and insights on how his almost 500-strong practice, AHMM, delivers sustainable design.

Hattie Hartman also speaks with Gary Clark about the current workstreams of the RIBA's Sustainable Futures Group.

For show notes, go to https://www.architectsjournal.co.uk/podcasts

Ep 14. AJ Climate Champions with Hattie Hartman. Architect Sarah Featherstone and planner Jennifer Ross, both members of the all-female VeloCity team, describe their 21st-century strategy for the English countryside: less cars, more bikes and new housing in village clusters linked to rail stations.

Ross explains why we desperately need a joined-up approach to spatial planning that focuses on villages clustered within a 7-mile radius to lure people out of their cars and onto bicycles and footpaths, and Featherstone reveals early proposals for Blenheim Estate which include Passivhaus housing and reinstated cycleways to facilitate school runs.

For show notes to this episode and to catch up on all AJ Climate Champions episodes, click here.

Episode 48. AJ Climate Champions with Hattie Hartman and Joe Jack Williams. Structural engineer Eva MacNamara of Expedition Engineering explains how we can radically reduce our use of concrete and how to better understand the biodiversity impacts of material choices.

In this episode, we dive into the tricky topic of concrete and unpick the widespread mantra that ‘concrete is bad’.  Concrete is ‘an addiction’ that has led to an obese construction industry, says Expedition’s MacNamara; it is not going to go away but we can radically reduce our use of it. She describes a porposed slab design for the Eden Project site in Dundee which would achieve an 80% reduction in concrete volume.

MacNamara stresses that ‘using less’ is much more impactful than substituting low-carbon concretes and notes that she repeatedly sees practitioners over-specifying. We discuss some of the nuances of concrete use: which applications are most appropriate, how to reduce the volumes we use, and why low-carbon concrete – especially GGBS – is not a silver bullet. We also touch on upcoming innovations including Seratech, ‘funnel’ slabs and smart crushing.

McNamara explains how to bring both carbon and biodiversity into the concrete procurement process. Highlighting findings from the recent report The Embodied Biodiversity Impacts of Construction Materials (Expedition/ICE, November 2023), she notes that 95% of biodiversity impacts occur off site and that the new biodiversity net gain requirements only address the 5% on site, so designers must look beyond a site’s boundary.

Finally, MacNamara advocates finding a place to innovate on every project. ‘We can make the most difference by using our projects as springboards for incubating innovation,’ she says.

For show notes and to catch up on all AJ Climate Champions episodes, click here.

Ep 13. AJ Climate Champions with Hattie Hartman. In our continuing series on landscape and the biodiversity crisis, we speak to rewilding pioneer Isabella Tree of the Knepp Estate in West Sussex, hailed as ‘one of the most exciting wildlife conservation projects in the UK.’

The conservationist and author explains why the proposed Buck Farm development – which goes before Horsham District Council this week – epitomises the current controversy between the upcoming Environment Bill and the government’s intended planning reforms.

For show notes to this episode and to catch up on all AJ Climate Champions episodes, click here.

12. AJ Climate Champions with Hattie Hartman. Continuing its focus on landscape, Climate Champions turns its attention to two recent high-profile competitions where green and blue infrastructure promise to drive the design.

First up is Thamesmead Waterfront, a 100-hectare riverfront site in Greenwich to be developed in a joint venture between Lendlease and Peabody, the site’s owner. To hear about the winning scheme, we speak to Phil Askew, director of landscape and placemaking at Peabody, and Selina Mason, director of masterplanning at Lendlease. 

The Home of 2030 competition called for innovative home designs that are ‘green, age-friendly and healthy’. We speak to Sarah Jones-Morris, director of Bristol-based Landsmith Associates and the landscape architect behind Igloo Regeneration’s winning proposal, about how green and blue infrastructure permeate the scheme. 

For show notes to this episode and to listen to all AJ podcasts, visit architectsjournal.co.uk/podcasts

11. AJ Climate Champions with Hattie Hartman. 

In this second episode on landscape, we speak to Jo Gibbons of landscape practice J&L Gibbons whose wide-ranging work encompasses both the Dalston Eastern Curve Garden in Hackney and Walpole Park in Ealing, the setting of John Soane’s Pitzhanger Manor.

Gibbons explains why she won’t go near a project unless she’s involved from the outset and why today, diversity of planting is essential for biosecurity. A frequent external examiner, Gibbons bemoans the fact that there are so few landscape architects, while in architecture schools, architects too often design landscapes with minimal landscape tuition.

In a news roundup, co-hosts Hattie Hartman and George Morgan unpick the furore surrounding the Serpentine Pavilion’s carbon negative claims and the alarming findings of the latest Committee on Climate Change report.

For show notes to this episode and to listen to all AJ podcasts, visit architectsjournal.co.uk/podcasts

10. AJ Climate Champions with Hattie Hartman.

Barnabas Calder charts the course of architectural history from hunter gatherers’ earliest mud and bone huts through coal-powered industrial Liverpool all the way to today’s search for regenerative design in Cork House (2019).

Calder explains how he got hooked on a climatic approach to architectural history and why he’s concluded that ‘small is good’, deciding to retrofit his current Liverpool terrace rather than upgrade to a larger home.

For show notes to this episode and to listen to all AJ podcasts, visit architectsjournal.co.uk/podcasts

9. AJ Climate Champions with Hattie Hartman. In this first of several episodes on landscape and biodiversity, we speak to Guy Shrubsole, policy and campaigns co-ordinator at Rewilding Britain and author of Who Owns England?

Shrubsole explains why land ownership patterns in England are at the root of the housing crisis, the extent to which agricultural practices are responsible for the ecological crisis and how rewilding can help restore biodiversity.

And in a brief news roundup, co-hosts Hattie Hartman and George Morgan discuss the launch of ACAN’s Natural Materials workstream, architecture practice Orms’ new open source Material Passports tool and the RIBA’s Mandatory Competences consultation.

For show notes to this episode and to listen to all AJ podcasts, visit architectsjournal.co.uk/podcasts

8. AJ Climate Champions with Hattie Hartman. Steve Webb of Webb Yates Engineers explains how to persuade clients to use more timber and stone, and Wilf Meynell shares Studio Bark’s approach to Victorian house extensions.

Webb describes what it will take to transform an industry fixated on concrete and steel, and outlines simple steps to decarbonise Victorian house extensions, while Meynell explains the budget challenges of low-carbon retrofit and why architecture is essentially political.

For show notes to this episode and to listen to all AJ podcasts, visit architectsjournal.co.uk/podcasts

7. AJ Climate Champions hosted by Hattie Hartman. Harry Paticas explains why he left architectural practice to focus on retrofitting schools, and how he educates schoolchildren on the climate emergency.

After more than a decade at Arboreal Architecture, the practice he co-founded in 2007, Paticas left in January 2021 to work full-time on RAFT, Retrofit Action for Tomorrow, a Lewisham-based community enterprise he founded that promotes low-carbon retrofit in primary schools. RAFT combines professional retrofit expertise with a hands-on educational programme. Equipping children with thermal cameras and teaching them rudimentary building physics with hot baked potatoes, Paticas is expanding the reach of his retrofit know-how.

And in a quick news roundup, co-hosts Hattie Hartman and George Morgan share views on ACAN’s student activism campaign, greenwashing and Passivhaus myth-busting.

For show notes to this episode and to listen to all AJ podcasts, visit architectsjournal.co.uk/podcasts

Bonus episode. AJ Climate Champions hosted by Hattie Hartman. Author and critic Owen Hatherley describes approaches to the retrofit of Modernist buildings, lessons learned from post-Soviet housing and why he thinks White Design’s straw bale Lilac Cohousing in Leeds could be a replicable new build approach. The AJ's Will Hurst explains the tactics and ambitions of the RetroFirst campaign, from engaging with MPs to raising public awareness, as well as the policy levers necessary to prioritise retrofit.   

In a quick news roundup, hosts Hattie Hartman and George Morgan share their views on Zaha Hadid Architects’ Forest Green Rovers timber stadium proposal and round up other sustainability news, including ACAN’s Carbon Footprint of Construction report.    

For show notes to this episode and to listen to all AJ podcasts, visit architectsjournal.co.uk/podcasts

6. Climate Champions hosted by Hattie Hartman. In the final episode in this series, German architect Anna Heringer talks to the AJ about mainstream building with earth, her 'Corona baby' – a birth space in the Vorarlberg region of Austria, and her pipeline of projects in Germany, Spain and Ghana. 

5. Climate Champions hosted by Hattie Hartman. This episode centres on the retrofit of Stock Orchard Street, Wigglesworth's home and office completed in 2001. The Stock Orchard Street retrofit, completed in 2020, tackled maintenance and repair, a deep environmental upgrade and rethinking the house for ageing gracefully.

For the first in a new six-part series on materials, Hattie is joined by co-host Joe Jack Williams to interview Martha Lewis, head of materials at Danish practice Henning Larsen.

Lewis argues that a baseline of health and environmental impacts should inform material specification, and explains why a holistic approach is essential to navigate the nuances of material selection. She describes how the European focus on life cycle analysis and the Global Warming Potential of materials is starting to be integrated with the earlier American focus on healthy materials and toxic chemical content.

‘The glut of information is a challenge of our time. How do we navigate too much information to make the right decisions?’ asks Lewis. She advocates for material passports which would consolidate the relevant data needed to make informed decisions: carbon emissions, chemical content and circularity. She also argues that certification schemes, despite their weaknesses, are the most effective route to ensuring that a project delivers on its sustainability aspirations.

Also in this episode, Lewis describes Unboxing Carbon, a database with an accompanying course which she has developed to upskill architects on the carbon aspects of material selection. Lewis has rolled out Unboxing Carbon across Henning Larsen’s 700-strong practice and also offers it to external practices.

For show notes and to catch up on all AJ Climate Champions episodes, click here.

4. Climate Champions hosted by Hattie Hartman. Diana Dina, head of sustainability and regenerative design at Haworth Tompkins, shares her insights on how to be a changemaker in a large architecture practice.

The episode also features a discussion with Lauren Shevills of ACAN on Foster + Partners and ZHA's controversial departure from Architects Declare. 

3. Climate Champions hosted by Hattie Hartman. Architect, author, educator and sustainability expert Sofie Pelsmakers shares insights on sustainable design from the Nordic region, and discusses the urgent need for top-down architecture curriculum reform.

2. Climate Champions hosted by Hattie Hartman. Mikhail Riches' Annalie Riches discusses the Stirling Prize-winning Goldsmith Street scheme, and the critical importance of learning from completed projects.

Sponsored by the Green Building Store.

1. Climate Champions hosted by Hattie Hartman. Buro Happold's director of sustainability explains why she felt she had to leave architecture and retrain as an engineer.